Struck by PO syndrome

[mike-s]

I was just about to suggest using a dremel/similar, have used it before and cutting it as far as you can and then using a cold chisel to split it one side and then the other (if needed) does the job quite well.

[Frank Z.]

Last last resort:
Working on well heads offshore, we used slugging (or striking) wrenches to remove big stubborn nuts. You can get sluggers in metric, but not much selection under 20mm.

http://www.royalsupply.com/store/pc/Metric-Offset-Handle-Striking-Wrenches-c2814.htm

Grab a 3 lb. sledge, eye protection, and a bad attitude. She'll break.

Good luck!

[earlfor]

Last last resort:
Working on well heads offshore, we used slugging (or striking) wrenches to remove big stubborn nuts. You can get sluggers in metric, but not much selection under 20mm.

http://www.royalsupply.com/store/pc/Metric-Offset-Handle-Striking-Wrenches-c2814.htm

Grab a 3 lb. sledge, eye protection, and a bad attitude. She'll break.

Good luck!

yeah, what is going to break is the output shaft in the transmission.

Earl